The pattern of synthesis and turnover of various components of the envelope of E. coli B/r during the cell division cycle will be analyzed. Turnover rates during growth in the same or enriched media will be determined in synchronized populations and the extent of turnover will be related to change in rates of cell division, chromosome replication and the initiation of new rounds. Cell mass at initiation of rounds of chromosome replication and at increase in rate of synthesis of envelope components (namely outer membrane proteins and phospholipids) will be determined at growth rates less and larger than 1.0 doubling/hr at 37 degrees C.